Seal means for axial flow pump and the like

ABSTRACT

Disclosed is means for preventing leakage from about the shaft of an axial flow pump, the shaft extending through a housing wall. The means includes a sleeve for the shaft which is fixed at one end to the housing wall and is flared at its other end adjacent the pump impeller. The flared end forms a housing for a centrifugal pump rotor on the shaft, the centrifugal pump rotor being arranged to pump counter to the axial flow pump to prevent liquid from rising in the sleeve and leaking from about the shaft.

United States Patent [1 1 Layne Oct. 23, 1973 1 sEAL MEANS FOR AXIAL FLOW PUMP AND THE LIKE [76] Inventor: Ronald Paul Layne, 233 Greystone Ln., Rochester, NY. 14618 [22] Filed: May 26, 1972 [21] Appl. No.1 257,387

[52] U.S. Cl. 415/110, 415/73, 417/424 [51] Int. Cl. F01d 11/00 [58] Field of Search 415/110, 73, 143; 417/424 [56] References Cited UNITED STATES PATENTS 3,416,729 12/1968 Ravitts et al 415/143 3,535,051 10/1970 Turner 415/109 2,468,704 4/1949 Pippin 417/424 2,470,563 5/1949 Jennings 417/424 2,624,286 11/1953 Smith 417/424 2,839,006 6/1958 Mayo 417/424 2,865,296 12/1958 Bungartz..... 415/143 3,160,106 12/1964 Ashworth 415/197 Primary Examiner-C. J. l-lusar Attorney-T. B. Roessel [5 7] ABSTRACT Disclosed is means for preventing leakage from about the shaft of an axial flow pump, the shaft extending through a housing wall. The means includes a sleeve for the shaft which is fixed at one end to the housing wall and is flared at its other end adjacent the pump impeller. The flared end forms a housing for a centrifugal pump rotor on the shaft, the centrifugal pump rotor being arranged to pump counter to the axial flow pump to prevent liquid from rising in the sleeve and leaking from about the shaft.

5 Claims, 1 Drawing Figure SEAL MEANS FOR AXIAL FLOW PUMP AND THE LIKE BACKGROUND OF THE INVENTION The present invention relates generally to a vertically oriented axial flow pump having a bottom located inlet and a top located outlet, wherein the drive shaft for the pump extends through an upper end wall of the housing pump. More particularly, the present invention relates to means for preventing leakage from about the drive shaft without the use of rotating pressure seals contacting and extending between the shaft and end wall.

Axial flow pumps usually have the impeller shaft extending through an end wall of the pump housing. Providing an effective seal between this end wall and the impeller shaft presents somewhat of a problem, particularly where the pump is arrnaged so that fluid flow is toward this end wall. Rotating seals or gaskets may be provided between the end wall and the impeller shaft, but these are not entirely suitable because of the wear problem and the need for periodic replacement of rotating seal.

In the present invention, there is no dynamic or rotating seal contacting and extending between the impeller shaft and the end wall of the pump housing through which the shaft extends. Instead, means are provided for directing the liquid immediately adjacent the impeller shaft in a direction away from this end wall, even though the normal pump flow is towards this end wall.

SUMMARY OF THE OF THE INVENTION The present invention may be characterized in one aspect thereof by the provision of an axial flow pump including a housing having an inlet and outlet; a housing end wall adjacent the pump outlet; an impeller shaft extending through an opening in the end wall; a'sleeve member about the impeller shaft, one end of the sleeve member being fixed to the end wall about the opening, and the other end of the sleeve member having a flared section forming a centrifugal pump housing adjacent the axial flow impeller on the shaft; and a centrifugal pump rotor on the shaft in the flared section arranged to pump liquid in the sleeve in an axial direction away from the end wall, wherein the action of the centrifugal pump balances the pressure produced in the sleeve by the axial flow impeller to prevent liquid from rising in the sleeve to the level of the opening.

OBJECTS OF THE INVENTION pumping liquid out of the sleeve counter to the action of the axial flow pump wherein liquid is prevented from rising up in the sleeve and leaking from the housing about the shaft.

These and other objects, advantages and characterizing features of the present invention will become more :apparent upon consideration of the following detailed description thereof, taken in connection with the accompanying drawings depicting the same.

DESCRIPTION OF THE DRAWINGS The sole FIGURE is a side elevation view partly broken away and in section showing the axial flow pump of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing, the axial flow pump of the present invention is generally designated at 10. The pump includes a tubular housing 12 depending from a top member 14. The top member functions as an end wall of the housing. The other end 16 of the housing forms an open pump inlet. End 16 may be connected to a reservoir of the liquid to be pumped by any suitable means, such as immersing the inlet below the level of liquid in reservoir 18, as shown, or by suitable conduct means, not shown. The pump outlet shown at 20 is above the level of liquid in reservoir 18.

Extending through an opening 22 in end wall 14 is the pump impeller shaft 24. The shaft extends down through the housing and carries on its lower end 26, a hub 28 and an axial flow impeller 30. Any suitable means such as a beltand pulley drive 44 can be used to rotate the impeller shaft. It should be appreciated that when the impeller shaft and hub is rotated, impeller 30 drives the liquid upwardly in housing 16 and out through discharge 20. If the discharge is located very close to end wall 14 or if the pump exerts a sufficient force, the entire housing 12, even that portion above the level of discharge 20, will be filled with liquid. Since this liquid is under pressure due to the action of impeller 30, there is the possibility of liquid leaking through opening 22 about shaft 24. This leakage of course can be prevented by a suitable rotating seal at this point. However, as set forth hereinabove, such rotating seals are not completely satisfactory .in that they wear and must be replaced periodically.

Means for eliminating the need of any rotating seal between wall opening'22 and impeller 24 is provided in the present invention by having a sleeve member 32 disposed about impeller shaft 24. The sleeve member has its upper end 34 fixed to end wall 14 in a fluid tight joint. If desired, a static seal such as an O-ring 36, can be located between the upper sleeve end 34 and wall 14. The lower end of the sleeve has an outwardly flared portion 38, which is disposed about the-upper portion 40 of impeller hub 28. I

The upper portion of the impeller hub is generally conical in shape to fit into the flared sleeve end. In addition, this portion of the hub is provided with a series of axially extending grooves 42 formed integral the hub. The flared sleeve end and upper hub-portion to gether form a centrifugal pump, the flared sleeve end being the pump housing, upper hub portion 40 being the rotor and grooves 42 being the pump vanes. This centrifugal pump formed by flared sleeve end 38 and hub portion 40 is arranged to pump fluid in a direction out of sleeve 32 and away from end wall 14 as the impeller shaft rotates. Thus, the flow of the centrifugal pump is axially opposed to the flow of the axial flow toward discharge 20. The action of impeller 20 also tends to force liquid upwardly through sleeve 32, and about impeller shaft 24. However, the action of centrifugal pump rotor 40 is to pump liquid out of the sleeve away from the end wall and towards the pump inlet.

The action of the centrifugal pump, plug the force of 5 gravity tending to move the fluid out of the sleeve and away from end wall 14 is sufficient to offset the head produced by the action of impeller 30. Thus, a pressure balance is established between the upward pressure in the sleeve produced by the axial flow pump and the downward pressure in the sleeve produced primarily by the centrifugal pump with the net result being that the liquid in the sleeve raises to a level which is short of the end wall 14. So long as the level ofliquid never rises to opening 22, there can be no leakage through this opening from about shaft 24, and, consequently, no need to provide a rotating seal contacting the shaft at this point.

Thus, it should be appreciated that the present invention accomplishes its intended objects in providing means for preventing leakage from about the impeller shaft of an axial flow pump without the need for any rotating seals contacting the shaft. While a preferred embodiment has been described, it should be obvious that various modifications are within the skill of the art. For example, a scrollor screw type pump can be provided on impeller shaft 28 rather than the centrifugal pump shown. Such an arrangement would eliminate the need for flaring one end of sleeve 32. Also, grooves 42 can be inclined on the hub to produce both centrifugal and axial flow.

Having thus described the invention in detail, what is claimed as new is:

1. An axial flow pump comprising:

a. an upright pump housing with an outlet adjacent the top thereof, the top of said housing being closed by an end wall having an opening therethrough;

b. an impeller shaft extending down through said opening into said housing including an axial flow impeller on said shaft for pumping liquid through said housing and outlet;

c. a sleeve disposed about said shaft, said sleeve having an upper end rigidly fixed to said end wall about said opening in a liquid tight seal and a lower end formed with an outwardly flared portion, the outer diameter of said sleeve being smaller than the outer diameter of said impeller; and

d. a centrifugal pump rotor on said shaft and located in said flared portion, said flared sleeve portion forming a centrifugal pump housing for said rotor with said rotor and flared portion arranged for pumping liquid from within said sleeve in a direction axially opposed to the direction of flow from said axial flow impeller, whereby liquid is prevented from leaking through said opening about said shaft.

2. An axial flow pump as set forth in claim 1, wherein said axial flow impeller includes a portion comprising said centrifugal pump rotor disposed in said sleeve flared portion.

3. An axial flow pump as set forth in claim 2, wherein said hub portion is generally conical and provided with vane means.

4. An axial flow pump as set forth in claim 3, wherein said vane means comprise axial extending grooves formed in said conical hub portion.

5. An axial flow pump as set forth in claim 1 comprising:

a. a hub on the lower end of said impeller shaft, said hub having a lower portion carrying said axial flow impeller and an upper portion; and

b. said upper hub portion being conical in shape and fitting-into said outwardly flared sleeve portion, said upper hub portion comprising said centrifugal pump rotor. 

1. An axial flow pump comprising: a. an upright pump housing with an outlet adjacent the top thereof, the top of said housing being closed by an end wall having an opening therethrough; b. an impeller shaft extending down through said opening into said housing including an axial flow impeller on said shaft for pumping liquid through said housing and outlet; c. a sleeve disposed about said shaft, said sleeve having an upper end rigidly fixed to said end wall about said opening in a liquid tight seal and a lower end formed with an outwardly flared portion, the outer diameter of said sleeve being smaller than the outer diameter of said impeller; and d. a centrifugal pump rotor on said shaft and located in said flared portion, said flared sleeve portion forming a centrifugal pump housing for said rotor with said rotor and flared portion arranged for pumping liquid from within said sleeve in a direction axially opposed to the direction of flow from said axial flow impeller, whereby liquid is prevented from leaking through said opening about said shaft.
 2. An axial flow pump as set forth in claim 1, wherein said axial flow impeller includes a portion comprising said centrifugal pump rotor disposed in said sleeve flared portion.
 3. An axial flow pump as set forth in claim 2, wherein said hub portion is generally conical and provided with vane means.
 4. An axial flow pump as set forth in claim 3, wherein said vane means comprise axially extending grooves formed in said conical hub portion.
 5. An axial flow pump as set forth in claim 1 comprising: a. a hub on the lower end of said impeller shaft, said hub having a lower portion carrying said axial flow impeller and an upper portion; and b. said upper hub portion being conical in shape and fitting into said outwardly flared sleeve portion, said upper hub portion comprising said centrifugal pump rotor. 